β-fructofuranosidases are enzymes that recognize fructose in a carbohydrate containing a terminal fructose residue and hydrolyze the bond at the fructose residue. Some β-fructofuranosidases have the activity of transferring fructose resulting from the hydrolysis to a receptor substrate. Specifically, fructose can be transferred to a carbohydrate or a non-carbohydrate substance using such a β-fructofuranosidase having this activity to produce a fructose-added carbohydrate.
Heretofore, for example, a method which involves contacting a sugar substrate with a carrier on which hyphae of koji mold carrying a β-fructofuranosidase are immobilized (Patent Literature 1) and a method using levansucrase derived from Zymomonas mobilis or extracellular invertase (Patent Literature 2) have each been disclosed as a method for producing a fructose-added carbohydrate using a β-fructofuranosidase.